Lymphedema quality of life questionnaire (LYMQOL): cross-cultural adaptation and validation in Italian women with upper limb lymphedema after breast cancer

Purpose: There is growing interest in measures that assess upper-limb lymphedema after breast cancer. Since no validated Italian version of the Lymphedema Quality of Life Questionnaire for upper limbs (LYMQOL-UL) exists, we aimed to culturally adapt and validate an Italian version (LYMQOL-UL-IT) in order to allow its use in Italian patients.Materials and methods: The LYMQOL-UL-IT was developed by means of forward-backward translation, review by an expert committee and a test of the pre-final version to evaluate its comprehensibility. The psychometric testing included reliability by internal consistency (Cronbach's alpha) and test-retest reliability (intraclass correlation coefficient, ICC(2.1)), measurement error by calculating the minimum detectable change (MDC95), construct validity by confirmatory factor analysis, and evaluation of a priori hypotheses about the correlations between the four LYMQOL-UL domains, single items of the LYMQOL-UL, and measures of health-related quality of life and pain intensity (Spearman's rank correlation coefficient).Results: The consensus-based version of LYMQOL-UL-IT was administered to 139 patients with upper-limb stable secondary iatrogenic lymphedema after breast cancer. The adapted questionnaire was well accepted as it was completed in less than 10 min, without missing answers or comprehension problems. Internal consistency was acceptable (alpha = 0.92-0.95). Test-retest reliability was good-to-excellent (ICC(2.1) = 0.73-0.96). The MDC95 for the four domains of the questionnaire was as follows: 0.64 scale points for Function, 0.40 for Appearance, 0.53 for Symptoms, and 0.81 for Mood. Factor analysis confirmed a 4-dimensional structure as originally conceived and the a priori hypotheses were met.Conclusion: The LYMQOL-UL-IT is reliable, sensitive to change and valid in patients with upper-limb stable secondary iatrogenic lymphedema after breast cancer. It can be used for clinical and research purposes.